Threshold Intervals

Threshold Intervals are repeated bouts of hard, steady cardio on a machine, lasting a few minutes each, with short rest between. They train your ability to hold a strong, sustainable pace just below your redline, building leg endurance, aerobic power, and core stability.

Choose a machine: rower, bike, or ski erg. Set the damper or resistance to your usual training setting. Strap in, grip the handles, and sit or stand tall with your feet fully planted. Check the monitor and pick a pace or power from your latest 30-minute time trial.

Start each interval at your target pace or power, not faster. Hold that same output for the entire work period. Keep your stroke or pedal cadence smooth and your posture tall. At the end of the interval, ease up and recover for the prescribed time. Repeat for all reps, trying to match the first interval's output on the last one.

Breathe rhythmically through your nose and mouth so you can only say one or two words at a time. Keep your ribs down and your core engaged so you can transfer power without slouching. Easier: shorten the work interval or slow the pace slightly while keeping the same feel. Harder: lengthen the interval or cut the rest, but keep every split within reach of the first.

Fault: Going out too hard and fading. Fix: Settle into your target from the first stroke or pedal; if you cannot finish the last rep at the same pace, start more conservatively next time.

Fault: Talking in full sentences. Fix: Aim for the one-to-two-word talk test; if you can chat easily, increase the pace, and if you cannot speak at all, back off slightly.

Fault: Inconsistent splits. Fix: Glance at the monitor each minute and adjust effort so every interval looks similar; chase even output, not a sprint.

Fault: Using an old threshold number. Fix: Re-test your 30-minute time trial every 6 to 8 weeks and update your target pace or power.